油酸钠联合六偏磷酸钠浮选不黏煤的机理研究

Mechanism of Non-caking Coal Flotation Using Sodium Oleateand Sodium Hexametaphosphate

以不黏煤为研究对象,通过红外光谱分析、诱导时间测定、泡沫性质分析和浮选实验研究了油酸钠和煤油对煤或矸石颗粒性质的影响及浮选效果,探讨了六偏磷酸钠作为分散剂降低浮选精煤灰分的可行性。结果表明:油酸根可与煤表面发生有效吸附,难与矸石发生吸附。油酸钠作用后的煤颗粒与气泡接触时间为30 ms时,黏附概率大于50%;煤油作用后的煤颗粒与气泡接触时间为500 ms时,黏附概率不足50%。油酸钠作用后的泡沫层较煤油作用后的泡沫层更稳定。随着油酸钠用量的增加,精煤产率显著增加,油酸钠体系浮选精煤产率是煤油体系浮选精煤产率的3倍~10倍,油酸钠体系浮选完善指标是煤油体系浮选完善指标的2倍~9倍。六偏磷酸钠用量为500 g/t(干煤泥)时,浮选精煤灰分降低了8.42%。油酸钠与六偏磷酸钠的联合使用,既保证了煤颗粒的浮选回收,又降低了浮选精煤灰分,可应用于我国低阶煤泥的清洁与资源化利用。

The Fourier transform infrared spectroscopy,induction time,froth layer properties and flotation tests were employed to investigate the effects of the sodium oleate and kerosene on the flotation of non-caking coal.In addition,the feasibility of using sodium hexametaphosphate as the dispersant to reduce the ash content of clean coal was discussed.The results show that the oleate can be adsorbed on the coal surface,but it is difficult to be adsorbed on the gangue.When the contact between the bubble and coal particles treated by the sodium oleate lasts approximately 30 ms,the adhesion probability is more than 50%.When the kerosene is used to treat coal particles,the 50%adhesion probability requires the contact duration longer than 500 ms.In addition,the froth of the sodium oleate system is significantly greater than that of the kerosene system.The yield of the clean coal increases significantly as the applied amount of the sodium oleate increases.The yield of the clean coal from the sodium oleate system is 3-10 times that from the kerosene system.The flotation perfection index of the sodium oleate system is 2-9 times that of the kerosene system.The flotation results using sodium hexametaphosphate as the dispersant show that when the amount of the sodium hexametaphosphate is 500 g/t,the ash content of the clean coal reduces by 8.42%than that without the use of the sodium hexametaphosphate.The combined use of the sodium oleate and the sodium hexametaphosphate not only guarantes the recovery of the non-caking coal particles,but also the qualifies ash content of the clean coal.Therefore,the proposed method can be applied to the clean utilization of difficult-to-float low-rank coal.